Heretofore, it has been customary to capture a radiographic image of a breast of a subject, for example, in the following manner. First, the breast is compressed and then image capturing conditions are set, which represent a tube voltage of a radiation source, an mAs value (the product of the tube current and an irradiation time for the radiation), the thickness of the compressed breast, and the types of a target and a filter that make up the radiation source. Then, the radiation source applies radiation to the compressed breast according to the set image capturing conditions. Radiation that has passed through the breast is converted into a radiographic image by a radiation detector. Thereafter, the image capturing conditions that were used during capturing of the radiographic image are displayed as an exposure dose record of the subject on a display device.
In a case where the doctor or radiological technician manually sets image capturing conditions and performs a radiographic image capturing process (manual radiographic image capturing process) according to the set image capturing conditions, without enabling an AEC (automatic exposure control) function, the doctor or radiological technician may set image capturing conditions in terms of image quality (contrast) of a radiographic image to be captured, without regard to the exposure dose applied to the subject. As a result, the subject may undergo a meaningless exposure to radiation.
According to the radiographic image capturing process of the conventional technique, value has been placed only on the image quality of radiographic images to be captured, and there has been a lack of interest in the exposure dose applied to the subject. In recent years, radiographic image capturing techniques for reducing the exposure dose applied to the subject have been disclosed in Japanese Laid-Open Patent Publication No. 2002-263097, Japanese Laid-Open Patent Publication No. 2004-173924, and Japanese Laid-Open Patent Publication No. 2010-167165.